// eofReaderFunc is an io.Reader that runs itself, and then returns io.EOF.
type eofReaderFunc func()

func (f eofReaderFunc) Read(p []byte) (n int, err error) {
	f()
	return 0, io.EOF
}

func TestReferer(t *testing.T) {
	tests := []struct {
		lastReq, newReq, explicitRef string // from -> to URLs, explicitly set Referer value
		want                         string
	}{
		// don't send user: